Not sure where else to go because the manufacturer's website has no forum and I can't wait to hear back from their tech support if they can't return my e-mails on the weekend. (I'm leaving town after the weekend, so if the drive is bad, it needs to get returned Monday at the latest). Hoping either someone here ran into the same issue and has a fix, or they can confirm that this is not normal behavior for this model so I can go get an exchange. I just bought this external hard drive (SimpleTech 1TB Pro Drive) today, and it works nicely until I don't use it for about 20-30 minutes. The light on the front of the device turns off, but the drive acts like it's still connected with everything appearing normal in Mac OS X. Then no matter what I do with the hard drive (Move files, browse files, unmount the drive or look at it with Disk Utility or Get Info) those tasks will hang, and the computer won't do anything at all until I flip the drive's power off. Then I get the standard "Device Disconnected" message you get when you don't properly disconnect a drive, and then everything starts working again. So basically, the hard drive is going to sleep, but Mac OS X isn't acknowledging it, and then the hard drive won't wake up no matter what I do. OS X waits for the HDD to do something, and it never does. I've had this same problem with a different drive before, but that was on an eSATA connection. I switched to only using that drive on FW800 and it has never had a problem since. This drive is on FW800 and now doing the exact same thing that other drive used to do, so I'm not sure what to do. Edit: Forgot to mention, I'm using a 2006 Mac Pro with Leopard 10.5.8.